1998 Mariner low compression?

Shakerking

Recruit
Joined
Oct 30, 2014
Messages
3
hello i am new too this forum and was wondering if 92 psi on all cylinders is too low for a 1998 Mariner 115 outboard? it is a motor i am looking at buying and everything on the motor checked out good until i did the compression test.
thank you very much,
-Shakerking
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,544
A little history on the engine would help to read between the lines....ok! The fact that they all read equal is a super big plus. The fact that they all read below the 120 that the Service Manual uses as a minimum before "you can expect problems" is bad. Butttttt if you gauge is in error, or you are not using it properly you may be good to go. If you can run the engine and it starts right up and accelerates within reason under load.....hole shot in a reasonable amount of time and reasonable top speed, then suspect your gauge.

Mark
 

Shakerking

Recruit
Joined
Oct 30, 2014
Messages
3
thanks for the quick reply. i really appreciate it! seems too run good, shift good, and start up good.
 

enginepower

Petty Officer 1st Class
Joined
Jul 5, 2014
Messages
260
Did you do this compression test on a cold motor? Had it been sitting for a while? Maybe your gauge isn't accurate. Try it again with a different gauge and after it has run about 5-10 minutes and see if you get better results. Since they were all even and it's running good, it's probably ok.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,044
These motors run on 2 cylinders at idle.------They still sound good running on a trailer.
 
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